1. Field of the Invention
The present invention relates to a driving device and an optical apparatus, such as a camera, having the driving device.
2. Description of the Related Art
Conventionally, stepping motors have been employed as driving means for driving lenses.
However, such a conventional arrangement has the following problem.
In general, a stepping motor involves unique variations in rotating torque (torque ripples) during a stepping operation. If the stepping motor is rotated, the driving part of the stepping motor produces a vibration, and this vibration is transmitted to a lens holding member and the like and causes the problem of producing noise.
There is also a device which is arranged to move a lens barrel, which is a driven object, along the optical axis by means of a voice coil motor to detect the position of a moving lens by means of a magneto-resistance element.
Since this driving device is of a so-called direct drive type, the noise problem can be solved, but a weight to be moved becomes the total of the weight of the lens barrel which is a driven object and the weight of a movable portion of the voice coil motor. As a result, a thrust force stronger than the thrust force required to move the lens barrel is needed, so that a voice coil motor of a large size must be prepared or a large electric power is needed.